Marie-Pier L'Hostie and Penny Powell, both from Montreal, shared these viral Facebook posts last week, warning about mold that might build up in the anti-spill guard of their children's sippy cups.

My friend Simon O'kanada wondered why his son was always sick. He broke the anti-spill top of his "Tommee Tippee" bottle and discovered mold inside the mouthpiece. It doesn't wash and can't be seen unless it is broken open. He called the company, and the lady on the phone laughed out out loud. Several moms on other groups have also discovered mold after my post in another Facebook group, so I'm sharing you. If you please, those who have these cups, pay attention! Being washed by hand or in the dishwasher, the mold will stay there!

The women wrote that their decision to share the posts came from a discussion in a Facebook group for mothers. Both told the story of a dad named Simon O'kanada who was wondering why his child kept getting sick.

My friend wondered why his son was still sick so he broke open the anti-spill guard of his Tommee Tippee glass and discovered mold inside the anti-spill top that does not wash that you can't see except if you break it open. He called the company and the lady on the other end laughed in his face. Several moms on the other group also found mold after my post about it in another group so I'm sharing with you. Those of you with these cups pay special attention, he has washed it with his hands and in the dishwasher, etc., and the mildew has stayed anyway! Share it!

After having received several messages from parents who have opened their children's anti-spill cup, it is important to do something, so for parents who discover that they have the same problem with the anti-spill top, please, I invite you to complain to consumer protection and also the customer service of the company described — thank you! Share in large numbers.

L'Hostie and Powell wrote that O'kanada finally decided to open up the anti-spill top of his son's sippy cup and discovered it was full of mold.

The part that was holding the mouthpiece together appears to be where most of the mold was building up.

Apparently, all of the parents were using a particular type of cup made by Tommee Tippee, an international baby products manufacturer.

All of the parents reported washing the cup numerous times, both by hand and in the dishwasher. But the mold still built up. On Facebook, L'Hostie's photos were shared over 45,000 times and Powell's over 85,000 times.

Both posts are full of comments from horrified parents, as well as parents reporting discovering similar mold buildups in their children's cups. Tommee Tippee's France team responded to the controversy on Monday.

"We learned, as a result of posts, that some people were not satisfied with the result of the sippy valves used in our sippy cups: We apologize for the inconvenience and we assure you that we are actively working on the subject," they wrote on Facebook.

"This is what was in the anti-leak guard of my son's bottle... But it was cleaned properly and regularly. We had to break open the top to discover this. I love your brand and your products. However, regarding the anti-leak valve, there is a real problem..."

And parents are arguing that the suggested cleaning methods don't actually fight mold.

WARNING: All the people who have been using anti-spill cups for some time THROW THEM OUT! Open your cups, remove the anti-spill guard and break it into two. Mold settles in the cap and makes children sick!! If you can, take pictures and join the other parents who have raised a complaint against the consumer service. Neither the dishwasher or washing by hand removes it!!

BuzzFeed News has reached out to Tommee Tippee to see if it has received any similar complaints from parents in the U.K. or the United States.

UPDATE

Feb. 24, 2016, at 13:16 PM

Tommee Tippee sent BuzzFeed News a statement regarding the controversy:

We always welcome parents’ feedback, comments and ideas. We continually develop our products and look for ways to improve them, so feedback from parents is vital to us. Positive feedback tells us we’re doing the right thing, but just as importantly, like all companies, we learn even more when negative experiences are brought to our attention.

We’ve sold millions of Sippee cups and have had some very positive feedback. However, we know from visitor posts that a few people have not had a good experience with the valve part of the cup. For this we sincerely apologise and we are actively following up on any concerns raised.

We understand that the wellbeing of little ones is paramount and we can reassure all parents that we have extensively tested the valves. We have also been testing them with a panel of 140 mums in the United States.

The results support that when used with recommended liquids (cold, light fluids including water and non-pulp juices) and cleaned in line with instructions, there are no problems. Difficulties have arisen though when liquids that are not recommended for use in the cups have been used, like thick formula milk, pulpy juice and warm liquids. We also recommend that cups are not left for long periods before being cleaned.

However, we do understand that there may be other factors that are difficult to replicate in our testing, so our Careline team would like to speak directly to any parents who are experiencing problems. This will allow us to hear their views, and replace the cup with an alternative of their choice. The number to call is 0 800 10 07 25.

We’ve also prepared a page on our website to help parents care for their cups and valves.

UPDATE - Tommee Tippee released another statement on Friday, saying that they are releasing a new cup with a piece that's easier to clean, and in the meantime, they are giving parents a transparent valve for free so they can check for mold.

Feb. 26, 2016, at 09:44 AM

Child health and wellbeing is at the heart of everything we do, and we’re taking the current concerns around our Sippee cups very seriously.

We’ve sold millions of Sippee cups globally and continue to receive great feedback, but we know from recent social media posts that some people have had problems cleaning the valve. For this we sincerely apologise.

We want everyone to be happy with our products and we always want to exceed expectations. We’ve therefore listened to our customers, and will be launching a new Sippee cup in the next few months.

The new cup will have a two piece valve that can be used with different types of liquid, and is easier to clean.

In the meantime, we are making transparent, see-through valves (see photograph) immediately available to any parents that have concerns. The see-through valve will enable parents to see inside, and give them confidence that the valve is clean, when used in line with recommended instructions.

Alternatively, we will be happy to provide parents with a different style cup if they’d prefer. Either option will be provided free of charge.

Anyone that would like a see-through valve or alternative cup should contact our Careline toll free on 1-877 248 6922, and one will be sent as quickly as possible.

The reported problems only relate to the one-piece valve on the Sippee range of cups, and do not affect any other Tommee Tippee product.